I R Chambers

University of Glasgow, Glasgow, Scotland, United Kingdom

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Publications (58)90.49 Total impact

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    ABSTRACT: To assess the impact of the duration and intensity of episodes of increased intracranial pressure on 6-month neurological outcome in adult and paediatric traumatic brain injury. Analysis of prospectively collected minute-by-minute intracranial pressure and mean arterial blood pressure data of 261 adult and 99 paediatric traumatic brain injury patients from multiple European centres. The relationship of episodes of elevated intracranial pressure (defined as a pressure above a certain threshold during a certain time) with 6-month Glasgow Outcome Scale was visualized in a colour-coded plot. The colour-coded plot illustrates the intuitive concept that episodes of higher intracranial pressure can only be tolerated for shorter durations: the curve that delineates the duration and intensity of those intracranial pressure episodes associated with worse outcome is an approximately exponential decay curve. In children, the curve resembles that of adults, but the delineation between episodes associated with worse outcome occurs at lower intracranial pressure thresholds. Intracranial pressures above 20 mmHg lasting longer than 37 min in adults, and longer than 8 min in children, are associated with worse outcomes. In a multivariate model, together with known baseline risk factors for outcome in severe traumatic brain injury, the cumulative intracranial pressure-time burden is independently associated with mortality. When cerebrovascular autoregulation, assessed with the low-frequency autoregulation index, is impaired, the ability to tolerate elevated intracranial pressures is reduced. When the cerebral perfusion pressure is below 50 mmHg, all intracranial pressure insults, regardless of duration, are associated with worse outcome. The intracranial pressure-time burden associated with worse outcome is visualised in a colour-coded plot. In children, secondary injury occurs at lower intracranial pressure thresholds as compared to adults. Impaired cerebrovascular autoregulation reduces the ability to tolerate intracranial pressure insults. Thus, 50 mmHg might be the lower acceptable threshold for cerebral perfusion pressure.
    Intensive Care Medicine 04/2015; DOI:10.1007/s00134-015-3806-1 · 7.21 Impact Factor
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    ABSTRACT: There are many serious and acute physiological conditions about which we have incomplete medical knowledge. To address this and develop effective treatments it is often the case that a wealth of clinical data is required for collection, analysis and feedback. Whilst such data often exists it is typically held in a variety of different formats and locations. This paper describes the EU FP7-funded Avert-IT project (www.avert-it.org), which has developed an integrated, realtime physiological data infrastructure (ICUnet) to address the specific issue of prediction of hypotensive events in the brain trauma domain. This system has been used to support a major multi-centre clinical trial. In this paper, the implementation and application of the ICUnet system is described, followed by the design and results of the clinical trial.
    Computer-Based Medical Systems (CBMS), 2012 25th International Symposium on; 01/2012
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    ABSTRACT: Hypotension is recognized as a potentially damaging secondary insult after traumatic brain injury. Systems to give clinical teams some early warning of likely hypotensive instability could be added to the range of existing techniques used in the management of this group of patients. By using the Edinburgh University Secondary Insult Grades (EUSIG) definitions for -hypotension (systolic arterial pressure <90 mmHg OR mean arterial -pressure <70 mmHg) we collected a group of ∼2,000 events by analyzing the Brain-IT database. We then constructed a Bayesian Artificial Neural Network (an advanced statistical modeling technique) that is able to provide some early warning when trained on this previously collected demographic and physiological data. Using EUSIG defined event data from the Brain-IT database, we identified a Bayesian artificial neural network (BANN) topology and constructed a series of datasets using a group of clinically guided input variables. This allowed us to train a BANN, which was then tested on an unseen set of patients from the Brain-IT database. The initial tests used a particularly harsh assessment criterion whereby a true positive prediction was only allowed if the BANN predicted an upcoming event to the exact minute. We have now developed the system to the point where it is about to be used in a two-stage Phase II clinical trial and we are also researching a more realistic assessment technique. We have constructed a BANN that is able to provide early warning to the clinicians based on a model that uses information from the physiological inputs; systolic and mean arterial pressure and heart rate; and demographic variables age and gender. We use 15-min SubWindows starting at 15 and 30 min before an event and process mean, slope and standard deviations. Based on 10 simulation runs, our current sensitivity is 36.25% (SE 1.31) with a specificity of 90.82% (SE 0.85). Initial results from a Phase I clinical study shows a model sensitivity of 40.95% (SE 6%) and specificity of 86.46% (SE 3%) Although this figure is low it is considered clinically useful for this dangerous condition, provided the false positive rate can be kept sufficiently low as to be practical in an intensive care environment. We have shown that using advanced statistical modeling techniques can provide clinical teams with useful information that will assist clinical care.
    Acta neurochirurgica. Supplement 01/2012; 114(114):39-44. DOI:10.1007/978-3-7091-0956-4_8
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    ABSTRACT: Hypotension is a recognized -secondary insult after traumatic brain injury (TBI). There are many definitions of hypotension, an often cited example being the Brain Trauma Foundation's current (2007) "Guidelines for the Management of Severe Traumatic Brain Injury," which defines hypotension as systolic pressure <90 mmHg. However, this same document declares "The importance of mean arterial pressure, as opposed to systolic pressure should also be stressed, …." Our work shows that when using the Edinburgh University Secondary Insult Grades (EUSIG) definitions, which require monitoring of both systolic and mean arterial pressures, that most hypotensive events are in fact triggered by a breach of the mean arterial level of 70 mmHg. We suggest that close monitoring of mean arterial pressure would enable clinical teams to avoid more potentially damaging hypotensive events. An analysis of 100 patients from the Brain-IT database was performed. Using the EUSIG definitions, 2,081 events can be obtained by analyzing the systolic and mean blood pressures on a minute by minute basis. A software program was written to identify and classify the trigger pattern for each event. A categorical analysis of these triggering patterns has been carried out. Our analysis shows that most events are triggered by a drop in mean arterial pressure. In fact a large number of events (91%) occur where the mean arterial pressure is below the threshold limits whereas the systolic pressure does not cross the 90 mmHg limit at all. We suggest that more emphasis should be placed on closely monitoring mean arterial pressure as well as systolic pressure when trying to guard against hypotensive problems in traumatically brain injured patients. In future work we will study the underlying physiological mechanisms and attempt to further classify concomitant conditions that may be contributing to the onset of a hypotensive event.
    Acta neurochirurgica. Supplement 01/2012; 114:45-9. DOI:10.1007/978-3-7091-0956-4_9
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    ABSTRACT: BackgroundThe BrainIT group works collaboratively on developing standards for collection and analyses of data from brain-injured patients and to facilitate a more efficient infrastructure for assessing new health care technology with the primary objective of improving patient care. European Community (EC) funding supported meetings over a year to discuss and define a core dataset to be collected from patients with traumatic brain injury using IT-based methods. We now present the results of a subsequent EC-funded study with the aim of testing the feasibility of collecting this core dataset across a number of European sites and discuss the future direction of this research network. MethodsOver a 3-year period, data collection client- and web-server-based tools were developed and core data (grouped into nine categories) were collected from 200 head-injured patients by local nursing staff in 22 European neuro-intensive care centres. Data were uploaded through the BrainIT website and random samples of received data were selected automatically by computer for validation by data validation staff against primary sources held in each local centre. Validated data were compared with originally transmitted data and percentage error rates calculated by data category. Feasibility was assessed in terms of the proportion of missing data, accuracy of data collected and limitations reported by users of the IT methods. FindingsThirteen percent of data files required cleaning. Thirty “one-off” demographic and clinical data elements had significant amounts of missing data (>15%). Validation staff conducted 19,461 comparisons between uploaded database data with local data sources and error rates were commonly less than or equal to 6%, the exception being the surgery data class where an unacceptably high error rate of 34% was found. Nearly 10,000 therapies were successfully recorded with start-times but approximately a third had inaccurate or missing “end-times” which limits the analysis of duration of therapy. Over 40,000 events and procedures were recorded but events with long durations (such as transfers) were more likely to have end-times missed. ConclusionsThe BrainIT core dataset is a rich dataset for hypothesis generation and post hoc analyses, provided that studies avoid known limitations in the dataset. Limitations in the current IT-based data collection tools have been identified and have been addressed. In order for multi-centre data collection projects to be viable, the resource intensive validation procedures will require a more automated process and this may include direct electronic access to hospital-based clinical data sources for both validation purposes and for minimising the duplication of data entry. This type of infrastructure may foster and facilitate the remote monitoring of patient management and protocol adherence in future trials of patient management and monitoring. KeywordsClinical network-Traumatic brain injury-Grid-Internet
    Acta Neurochirurgica 11/2010; 152(11):1859-1871. DOI:10.1007/s00701-010-0719-1 · 1.79 Impact Factor
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    ABSTRACT: There are many serious and acute physiological conditions about which we have incomplete medical knowledge that can support optimal healthcare intervention. To develop effective treatments a wealth of clinical data is required for collection, analysis and feedback. Such data often does exist but is typically held in a variety of different formats and locations. This paper describes the EU FP7-funded Avert-IT project (www.avert-it.org), which has developed an integrated, real-time physiological data grid infrastructure (Hypo Net) to address the specific issue of prediction of hypotensive events in the brain trauma domain and is currently being used as part of a large multi-centre clinical trial. The implementation and application of the Hypo Net system is described here.
    Sixth International Conference on e-Science, e-Science 2010, 7-10 December 2010, Brisbane, QLD, Australia; 01/2010
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    ABSTRACT: By developing, implementing and delivering a noise reduction intervention programme, we aimed to attempt to reduce the high noise levels on inpatient wards. Sleep is essential for human survival and sleep deprivation is detrimental to health and well being. Exposure to noise has been found to disrupt sleep in hospitalised patients which is to be expected as noise levels have been measured and reported as high. A primarily nursing focused, multi-method approach, involving development of clinical guidelines, ward environment review and a staff noise awareness and education programme, was used to target mainly nursing staff plus other healthcare staff on three wards within one hospital. This practice development initiative was carried out in three key phases (1) Preaudit of ward noise levels, (2) The development, implementation and delivery of a noise reduction intervention programme, (3) Postaudit of ward noise levels. Preintervention average peak decibel levels over 24 hours were found to be 96.48 dB(A) and postintervention average peak decibel levels were measured at 77.52 dB(A), representing an overall significant reduction in noise levels (p < 0.001). This study describes one way to reduce peak noise levels on inpatient hospital wards. Sleep deprivation is detrimental to patients with acute illness, so any developments to improve patients' sleep are important. Nurses have a key role in leading, developing and implementing changes to reduce peak noise levels on inpatient wards in hospitals. This nurse-led practice development programme has demonstrated how improvements can be achieved by significantly reducing peak noise levels using simple multi-method change strategies.
    Journal of Clinical Nursing 10/2009; 18(23):3316-24. DOI:10.1111/j.1365-2702.2009.02897.x · 1.26 Impact Factor
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    ABSTRACT: The ability to predict adverse hypotensive events, where a patient's arterial blood pressure drops to abnormally low (and dangerous) levels, would be of major benefit to the fields of primary and secondary health care, and especially to the traumatic brain injury domain. A wealth of data exist in health care systems providing information on the major health indicators of patients in hospitals (blood pressure, temperature, heart rate, etc.). It is believed that if enough of these data could be drawn together and analysed in a systematic way, then a system could be built that will trigger an alarm predicting the onset of a hypotensive event over a useful time scale, e.g. half an hour in advance. In such circumstances, avoidance measures can be taken to prevent such events arising. This is the basis for the Avert-IT project (http://www.avert-it.org), a collaborative EU-funded project involving the construction of a hypotension alarm system exploiting Bayesian neural networks using techniques of data federation to bring together the relevant information for study and system development.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 08/2009; 367(1898):2679-90. DOI:10.1098/rsta.2009.0042 · 2.86 Impact Factor
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    ABSTRACT: The BrainIT group works collaboratively on developing standards for collection and analyses of data from brain injured patients towards providing a more efficient infrastructure for assessing new health technology. Materials and methods Over a 2 year period, core dataset data (grouped by nine categories) were collected from 200 head-injured patients by local nursing staff. Data were uploaded by the BrainIT web and random samples of received data were selected automatically by computer for validation by data validation (DV) research nurse staff against gold standard sources held in the local centre. Validated data was compared with original data sent and percentage error rates calculated by data category. Findings Comparisons, 19,461, were made in proportion to the size of the data received with the largest number checked in laboratory data (5,667) and the least in the surgery data (567). Error rates were generally less than or equal to 6%, the exception being the surgery data class where an unacceptably high error rate of 34% was found. Conclusions The BrainIT core dataset (with the exception of the surgery classification) is feasible and accurate to collect. The surgery classification needs to be revised.
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    ABSTRACT: The aim of this study was to determine the relationship between apolipoprotein E (APO E) alleles, the amount of cerebral perfusion pressure (CPP) insult and outcome in children after brain trauma. In a prospective two-centre case-control study, the APO E genotypes of 65 critically ill children admitted after brain trauma were correlated with age-related CPP insult quantification, conscious state at the time of discharge from intensive care and global outcome at 6 months post-injury. One hundred sixty healthy age- and sex-matched children were genotyped as controls. The CPP insult level among the e4 carriers with poor outcome was significantly less than the non-e4 carriers (p=0.03). Homozygotic e3 patients with good recovery did so despite having suffered nearly 26 times more CPP insult than those who were not e3 homzygous (p=0.02). Different APO E alleles may potentially affect cerebral ischaemic tolerance differently in children after brain trauma.
    Child s Nervous System 11/2008; 25(1):47-54. DOI:10.1007/s00381-008-0723-4 · 1.16 Impact Factor
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    ABSTRACT: ObjectiveTo assess the use of hyperventilation and the adherence to Brain Trauma Foundation-Guidelines (BTF-G) after traumatic brain injury (TBI). SettingTwenty-two European centers are participating in the BrainIT initiative. DesignRetrospective analysis of monitoring data. Patients and participantsOne hundred and fifty-one patients with a known time of trauma and at least one recorded arterial blood–gas (ABG) analysis. Measurements and resultsA total number of 7,703 ABGs, representing 2,269 ventilation episodes (VE) were included in the analysis. Related minute-by-minute ICP data were taken from a 30min time window around each ABG collection. Data are given as mean with standard deviation. (1) Patients without elevated intracranial pressure (ICP) (<20mmHg) manifested a statistically significant higher PaCO2 (36±5.7mmHg) in comparison to patients with elevated ICP (≥20mmHg; PaCO2: 34±5.4mmHg, P<0.001). (2) Intensified forced hyperventilation (PaCO2≤25mmHg) in the absence of elevated ICP was found in only 49 VE (2%). (3) Early prophylactic hyperventilation (<24h after TBI; PaCO2≤35mmHg, ICP<20mmHg) was used in 1,224 VE (54%). (4) During forced hyperventilation (PaCO2≤30mmHg), simultaneous monitoring of brain tissue pO2 or SjvO2 was used in only 204 VE (9%). ConclusionWhile overall adherence to current BTF-G seems to be the rule, its recommendations on early prophylactic hyperventilation as well as the use of additional cerebral oxygenation monitoring during forced hyperventilation are not followed in this sample of European TBI centers. DescriptorNeurotrauma
    Intensive Care Medicine 09/2008; 34(9):1676-1682. DOI:10.1007/s00134-008-1123-7 · 5.54 Impact Factor
  • R A Minns · P A Jones · I R Chambers
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    ABSTRACT: Useful information (both clinical and pathophysiological) which may be extracted from intracranial pressure (ICP) recordings include: (1) the mean level of ICP (and CPP), (2) cerebrovascular autoregulation status, (3) the intracranial pulse pressure (the pulse wave index, ICPpp/ICPm) or the pressure-volume compensatory reserve index (RAP) and (4) the presence of any abnormal ICP waveform. This paper describes a slow frequency ICP waveform in children with TBI and postulates the pathophysiological basis and whether it contains clinically useful detail. Children admitted to the Regional Head Injury Service in Edinburgh with TBI have continuously monitored ICP, MAP, CPP, and other physiological data (stored at a 1-min resolution). Slow frequency waveforms were noted, prompting a review of the stored monitoring from all cases over a 10 year period. Episodic slow pressure waves were detected in 11 of 122 severely head-injured (HI) children. The waveforms were detected in children of all ages (1.6-15 years) in the ICP signal, which were in phase with similar fluctuations in the MAP, CPP, and HR signals. Their mean periodicity was 1 per 7 min (range 1 per 5-10 min), with a mean ICP pulse wave amplitude of 5.45 mmHg (range 4-7.5), and mean MAP pulse wave amplitude (pulse pressure) of 10.4 mmHg (range 4-15 mmHg). The duration was variable (range approx 2 h to 4.5 days). They were detected in the preterminal phase after serious HI, as well as in those children who made an independent recovery (GOS 4/5). The waves were not related to the mean levels of ICP, CPP, MAP, temperature or the state of cerebrovascular autoregulation. We postulate that these previously unreported slow waveforms may reflect the very low frequency (VLF) and ultra low frequency (ULF; < or = 1 per 5 min) components of heart rate and arterial blood pressure variability.
    Acta neurochirurgica. Supplement 02/2008; 102:85-8. DOI:10.1007/978-3-211-85578-2_17
  • P A Jones · I R Chambers · R A Minns · T Y M Lo · L M Myles · A J W Steers
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    ABSTRACT: Secondary pathophysiological CPP insult is related to outcome after head injury, and improved management would be expected to reduce secondary brain insult. Paediatric head injury management guidelines have been published in recent years, by SIGN (2000), RCPCH (2001), NICE (June 2003), and jointly by Critical/Intensive Care Societies (C/ICS July 2003). We investigated whether outcome of children's head injury (and total burden of secondary CPP insult) has changed (1) annually; (2) before and after the introduction of any HI guidelines, and (3) following other service changes. Seventy-six children (aged 1-14 years with severe HI) were admitted to the Edinburgh Regional Head Injury Service between 1989 and 2006, and dichotomised at various time points and compared in terms of: demographic factors, intracranial pressure (ICP), cerebral perfusion pressure (CPP) insults [e.g. age-banded pressure-time index (PTI)], and Glasgow Outcome Scale (GOS) score (assessed at 6 months post injury). When dichotomised around the SIGN guidelines, there were no statistically significant differences between the two group's demography or in primary brain injury, but the outcomes were different (p = 0.03), with 6 vs 4 GOS1 (died), 2 vs 4 GOS3 (severely disabled), 5 vs 16 GOS4 (moderately disabled) and 23 vs 14 GOS5 (good recovery), when comparing before and after year 2000. GOS4 was significantly different (chi-square = 7.99, p < 0.007). There was a (non-significant) trend for the later years to have longer insult durations of ICP, hypertension, CPP, hypoxia, pyrexia, tachycardia and bradycardia, greater PTI for both CPP and ICP, and more CPP insults (p = 0.003). There was, however, significantly less CPP insult (p = 0.030) after the introduction of the more management-oriented C/ICS guidelines. The most recent paediatric HI guidelines appear to have reduced the burden of secondary insult, but more time is required to determine if this will be reflected in improved outcomes.
    Acta neurochirurgica. Supplement 02/2008; 102:81-4. DOI:10.1007/978-3-211-85578-2_16
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    ABSTRACT: The BrainIT group works collaboratively on developing standards for collection and analyses of data from brain injured patients towards providing a more efficient infrastructure for assessing new health technology. Over a 2 year period, core dataset data (grouped by nine categories) were collected from 200 head-injured patients by local nursing staff. Data were uploaded by the BrainIT web and random samples of received data were selected automatically by computer for validation by data validation (DV) research nurse staff against gold standard sources held in the local centre. Validated data was compared with original data sent and percentage error rates calculated by data category. Comparisons, 19,461, were made in proportion to the size of the data received with the largest number checked in laboratory data (5,667) and the least in the surgery data (567). Error rates were generally less than or equal to 6%, the exception being the surgery data class where an unacceptably high error rate of 34% was found. The BrainIT core dataset (with the exception of the surgery classification) is feasible and accurate to collect. The surgery classification needs to be revised.
    Acta neurochirurgica. Supplement 02/2008; 102:217-21. DOI:10.1007/978-3-211-85578-2_42
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    ABSTRACT: The BrainIT project was conceived in 1997 and has grown into an international collaboration with the purpose of gathering high time resolution data from head injured patients utilising standardised methodologies. From 1998, 22 participating neuroscience centres collected three main types of information: demographic, physiological data and clinical treatment information. A data collection solution was provided for each centre dependent on their existing facilities and data were collected for the duration of monitoring as defined by the routine care in each centre. On completion of ICP monitoring all personal information was removed and then transferred to Glasgow via the internet where it was converted into a standard format and entered into a central database. Outcome was measured using the extended Glasgow Outcome Score using an interview questionnaire. Data has been obtained from a total of 349 patients (277 male and 72 female) The age of these patients ranged from 1 to 87 years (median 31); 145 had been involved in a traffic accident and 32 were pedestrians; 78 had suffered a fall; 24 were assaulted and the remaining 70 of other causes. A large amount of physiological data was collected (e.g. BP 2,531 days, ICP 2,212 days in total). This dataset has provided the opportunity to perform unique analysis and these include the statistical features of blood pressure, diurnal variations in ICP, optimal sampling rate determination and a comparison of summary measures of secondary insults. This challenging collaboration has brought together a large number of centres and developed a successful clinical research network focussed on improving the treatment of head injured patients. It has successfully collected a vast quantity of high quality data that provides a rich source for analysis and hypothesis testing.
    Acta neurochirurgica. Supplement 02/2008; 102:223-7. DOI:10.1007/978-3-211-85578-2_43
  • I R Chambers · D Martin · A Clark · A Nicklin · A D Mendelow · P Mitchell
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    ABSTRACT: There is considerable interest in surgical decompression as a management strategy (RescueICP) for intractable intracranial hypertension. After such an operation measurements of intracranial pressure (ICP) and thus cerebral perfusion pressure (CPP) become less meaningful. Measurements of the biomechanical properties of the brain may be one measure capable of detecting changing status of such patients. However these properties of the brain are neither documented or well understood. We have developed an indentation probe capable of making measurements of human brain stiffness. The device consists of an indenting tip of depth 2 mm and diameter 12 mm surrounded by an annular body of 20 mm diameter. Measurements are made by two load cells, connected through interface electronics to a laptop computer. Laboratory measurements show the probe to provide accurate and repeatable measurements over a range of zero to 10N. Inter-operator variability from six healthcare professionals had a coefficient of variance of 8.75%. Measurements obtained during surgery from a patient undergoing tumour resection were towards the lower end of the device's measurable range. We have determined that this indentation device has a linear response and that the inter- and intra-operator variability is low. Although the device is still in an early stage of development, preliminary results during intracranial surgery demonstrate that this device is capable of measuring in-vivo tissue stiffness. Further work is required to derive a quantitative "stiffness index" from the two load curves. In addition a standard operation method is required so that consistent and repeatable measurements are made. The device may be of value in assessing patients after decompressive craniectomy.
    Acta neurochirurgica. Supplement 02/2008; 102:287-9. DOI:10.1007/978-3-211-85578-2_54
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    A Clark · T N S Clarke · B Gregson · P N A Hooker · I R Chambers
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    ABSTRACT: The clinical estimation of pupil size and reactivity is central to the neurological assessment of patients, particularly those with or at risk of neurological damage. Health care professionals who examine pupils have differing levels of skill and training, yet their recordings are passed along the patient care pathway and can influence care decisions. The aim of this study was to determine if any statistical differences existed in the estimation of pupil size by different groups of health care professionals. A total of 102 health care professionals working in the critical care environment were asked to estimate and record the pupil size of a series of 12 artificial eyes with varying pupil diameter and iris colour. All estimations were performed indoors under ambient lighting conditions. Our results established a statistically significant difference between staff groups in the estimation of pupil size. The demonstrated variability in pupil size estimation may not be clinically significant. However, it remains desirable to have consistency of measurement throughout the patient care pathway.
    Emergency Medicine Journal 07/2006; 23(6):440-1. DOI:10.1136/emj.2005.030247 · 1.78 Impact Factor
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    ABSTRACT: The principal strategy for managing head injury is to reduce the frequency and severity of secondary brain insults from intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and hence improve outcome. Precise critical threshold levels have not been determined in head injured children. To create a novel pressure-time index (PTI) measuring both duration and amplitude of insult, and then employ it to determine critical insult thresholds of ICP and CPP in children. Prospective, observational, physiologically based study from Edinburgh and Newcastle, using patient monitored blood pressure, ICP, and CPP time series data. The PTI for ICP and CPP for 81 children, using theoretical values derived from physiological norms, was varied systematically to derive critical insult thresholds which delineate Glasgow outcome scale categories. The PTI for CPP had a very high predictive value for outcome (receiver operating characteristic analyses: area under curve = 0.957 and 0.890 for mortality and favourable outcome, respectively) and was more predictive than for ICP. Initial physiological values most accurately predicted favourable outcome. The CPP critical threshold values determined for children aged 2-6, 7-10, and 11-15 years were 48, 54, and 58 mm Hg. respectively. The PTI is the first substantive paediatric index of total ICP and CPP following head injury. The insult thresholds generated are identical to age related physiological values. Management guidelines for paediatric head injuries should take account of these CPP thresholds to titrate appropriate pressor therapy.
    Journal of Neurology Neurosurgery & Psychiatry 03/2006; 77(2):234-40. DOI:10.1136/jnnp.2005.072215 · 5.58 Impact Factor
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    ABSTRACT: Studies of therapeutic interventions and management strategies on head injured patients are difficult to undertake. BrainIT provides validated data for analysis available to centers that contribute data to allow post-hoc analysis and hypothesis testing. Both physiological and intensive care management data are collected. Patient identification is eliminated prior to transfer of data to a central database in Glasgow. Requests for missing/ ambiguous data are sent back to the local center. Country coordinating centers provide advice, training, and assistance to centers and manage the data validation process. Currently 30 centers participate in the group. Data collection started in January 2004 and 242 patients have been recruited. Data validation tools were developed to ensure data accuracy and all analysis must be undertaken on validated data. BrainIT is an open, collaborative network that has been established with primary objectives of i) creating a core data set of information, ii) standardizing the collection methodology, iii) providing data collection tools, iv) creating and populating a data base for future analysis, and v) establishing data validation methodologies. Improved standards for multi-center data collection should permit the more accurate analysis of monitoring and management studies in head injured patients.
    Acta neurochirurgica. Supplement 02/2006; 96:7-10.
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    ABSTRACT: An ultrasonic method was used to non-invasively measure intracranial blood volume (IBV) pulse waveforms. This technology has previously shown a strong association between invasively recorded ICP pulse waves and non-invasively recorded IBV pulse waves. The objective of the present study was to investigate the diagnostic value of non-invasively measured IBV pulse waves in the cases of different pathologies. A total of 75 patients were examined and these included cases of acute, chronic and stabilized hydrocephalus, spinal cord injury and terminal blood flow. These were compared to a control group of 53 healthy volunteers. The object of comparison was normalized and averaged IBV pulse waves. Pathological IBV pulse waveforms were compared with IBV pulse waveforms of the normal group using sub-wave values, the area under waveform curve and the Euclidean distance calculation. The non-invasively measured IBV pulse waveform is not significantly dependent on acoustic path, gender or age. A detectable change in IBV pulse waveform shape was observed in situations when disturbance in intracranial hydrodynamics was present, e.g. during hypoventilation tests, in cases of terminal blood flow and hydrocephaly, depicting the level of hydrocephalus activity and the patient's compensatory capabilities as well as the effect of treatment.
    Physiological Measurement 01/2006; 26(6):1019-32. DOI:10.1088/0967-3334/26/6/011 · 1.62 Impact Factor

Publication Stats

669 Citations
90.49 Total Impact Points

Institutions

  • 2012
    • University of Glasgow
      Glasgow, Scotland, United Kingdom
  • 2008–2012
    • James Cook University
      Townsville, Queensland, Australia
  • 1993–2008
    • The Newcastle upon Tyne Hospitals NHS Foundation Trust
      • • Department of Neurosurgery
      • • Regional Neurosciences Centre
      Newcastle-on-Tyne, England, United Kingdom
  • 2005
    • Uppsala University Hospital
      • Section for Neurosurgery
      Uppsala, Uppsala, Sweden
  • 1990–2000
    • Newcastle University
      Newcastle-on-Tyne, England, United Kingdom